Vitamin B(12) deficiency-induced pseudothrombotic microangiopathy without macrocytosis presenting with acute renal failure: a case report

BACKGROUND: Vitamin B(12) deficiency-induced thrombotic microangiopathy, known as pseudothrombotic microangiopathy, is a rare condition which resembles the clinical features of thrombotic thrombocytopenic purpura but requires a markedly different treatment. Most cases of vitamin B(12) deficiency have only mild hematological findings, but in approximately 10% of patients life-threatening conditions have been reported. CASE PRESENTATION: We report a case of a 46-year-old Moroccan man presenting with severe hemolytic anemia, thrombocytopenia, and renal failure in absence of macrocytosis, thus mimicking a genuine thrombotic thrombocytopenic purpura. Rapid improvement of renal function observed with only hydration and transfusions of packed red blood cells and the presence of pancytopenia suggested a bone marrow deficiency associated to a hemolytic component of unclear origin. Detection of low levels of vitamin B(12) and rapid restitutio ad integrum with its replacement supported the diagnosis of pseudothrombotic thrombocytopenic purpura caused by vitamin B(12) deficiency. CONCLUSIONS: Diagnosis of pseudothrombotic thrombocytopenic purpura caused by vitamin B(12) deficiency might be difficult. Awareness of clinicians toward this differential diagnosis might spare patients from unnecessary therapeutic plasma exchange that is burdened by morbidity and mortality. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13256-018-1815-8) contains supplementary material, which is available to authorized users.